1) Field of the Invention
This invention relates to novel polyamide-hydrogenated polybutadiene-acrylonitrile copolymers and to a process for producing the same.
2) Description of the Related Arts
Polybutadiene has been known to possess a flexible molecular structure, and a polystyrene-polybutadiene copolymer has been known to be an excellent thermoplastic elastomer. However, this copolymer has the problems of softening at a low temperature and being unable to exhibit any sufficient performance at a temperature range exceeding 120.degree. C. In order to solve these problems, a polyamide-polybutadiene type block copolymer has been suggested in which a polystyrene component is substituted by a polyamide component (Japanese Patent Publication No. 3171/87).
Since this block copolymer has problems in terms of its solubility in an organic solvent and its compatibility with other polymers, a polyamide-polybutadiene-acrylonitrile block copolymer has been disclosed in which these problems are improved upon without impairing its thermal resistance (Japanese Patent Application No. 2-105290). This block copolymer, however, has the disadvantage of being unable to melt-mold. A polyamide-hydrogenated type polybutadiene block copolymer has been suggested as one which improves upon this point (Japanese Patent Application No. 2-72192).
However, although the above-described polyamide-acrylonitrile-butadiene type block copolymer, polyamide-polybutadiene block copolymer, and the like which have hitherto been suggested have excellent thermal resistance, high solubility in organic solvents, good compatibility, etc., they have the problems of generating gases (particularly butadiene and cyano type harmful gases) during the thermal decomposition, and being unable to melt-mold. The polyamide-hydrogenated polybutadiene-acrylonitrile copolymers in which this point is improved is capable of melt-molding, but has the problems of compatibility, adhesive properties, etc. in combining with specific macromolecular materials.
This invention has been achieved in light of the problems in the conventional arts as described above.